Existing DNN methods seek to directly regress the relative position and rotation terms [1]}, [2]}, [3]}:
\(\Delta {\mathbf {q}} &\!=\!{^{G}_{I}{\bar{\mathbf {q}}}}(t_{k})^{-1}{^{G}_{I}{\bar{\mathbf {q}}}}(t_{k+1}) \\\Delta {\mathbf {p}} &\!=\!{^G_I \mathbf {R}^T}(t_k) \left( ^{G} {\mathbf {p}}_{I}(t_{k+1}) \!-\! {}^{G} {\mathbf {p}}_{I}(t_{k}) \right)\) 
